Apache Calcite Avatica 1.8.0 continues the focus on compatibility with previous versions while also adding support for authentication between Avatica client and server. Performance, notably on the write-path, is also major area of improvement in this release, increasing as much as two to three times over previous versions with the addition of new API support. The documentation for both users and developers continues to receive improvements.
Authentication is a major theme of this release, providing multiple layers of additional authentication mechanisms over previous versions. In these earlier versions, the only authentication provided by Avatica was achieved via the JDBC URL’s standard user and password options. These have always been passed directly into the backend database’s authentication system, but not all databases provide username and password based authentication systems. CALCITE-1173 adds Avatica-level authentication over HTTP Basic and HTTP Digest authentication mechanisms. These are provided specifically for the case when Avatica is used with a database that does not already provide its own authentication implementation.
Some systems rely on Kerberos for strong, centrally- managed authentication. CALCITE-1159 introduces Kerberos-based authentication for clients via SPNEGO. The Avatica server can be configured to only allow clients with a valid Kerberos ticket, optionally, also passing this information to the backend database to implement basic “impersonation” (where the Avatica server issues requests on behalf of the end user).
Building on top of the work done in Avatica-1.7.0 in CALCITE-1091,
this release also contains CALCITE-1128 which
implements the batch-oriented JDBC APIs on
Statement. Through careful inspection, it
was observed that the overall performance of Avatica clients in 100% write workloads was
dominated by the cost of the HTTP calls. By leveraging the
Statement#executeBatch() API calls, clients can efficiently batch multiple updates
in a single HTTP call. In testing this over the previous single HTTP call per update with
Apache Phoenix, it was observed that performance increased by
two to three times, bringing Avatica’s performance on par with the Phoenix “native” driver.
Returning back to compatibility, a new component appears in this release which is designed to test versions of Avatica against each other. CALCITE-1190 introduces a “Technology Compatibility Kit” (TCK) which automates the testing of one version of Avatica against other versions. To further ease this testing, a runnable JAR to launch an HSQLDB instance and an Avatica server also makes it debut with these changes. This TCK makes it much easier to run tests of newer clients against older servers and vice versa. Validating the backwards compatibility that is being built is extremely important to be confident in the guarantees being provided to users.
Finally, a number of bugs are also fixed in the Protocol Buffer wire API. Some of these include CALCITE-1113 and CALCITE-1103 which fix how certain numbers are serialized, CALITE-1243 which corrects some fields in Protocol Buffer messages which were incorrectly marked as unsigned integers instead of signed integers, and CALCITE-1209 which removes incorrect parsing of binary fields as Base64-encoded strings. All of these issues are fixed in a backwards-compatible manner and should have no additional negative impact on older clients (older clients will not break, but they may continue to return incorrect data for certain numbers).
For users of the Avatica driver, a new client reference page is added which details the options that are available in the Avatica JDBC Driver’s URL. The wire API documentation for Protocol Buffers continues to receive updates as the API continues to evolve.